Latch with fusible release



Feb. 23, 1965 w. SHEPHERD LATCH wm-x FUSIBLE RELEASE Filed Feb. 25. 1963 INVENTOR. WYLEY SHEPHERD BY SMMLIECS TORNEYS.

United States Patent 3,170,546 LATCH WITH FUSIBLE RELEASE Wyley Shepherd, 1943 NW. 1st Court, Miami, Fla. Filed Feb. 25, 1963, Ser. No. 260,557 2 Claims. (Cl. 189-50) The present invention relates to a fire-safety device in which a closure of a building is automatically unlatched when the temperature Within the building rises to a predetermined level, and more'particularly to a building construction including a closure provided with a latch having a fusible release.

It is an object of the present invention to provide building construction having a closure that automatically opens in the event of a fire.

Another object of the present invention is the provision of fire-safety constructions which provide access to the interior of a building at the time of a fire.

I Still another object of the present invention is the provision of latch assemblies that can be selectively locked in latched relationship against unauthorized opening but that release in the event of fire regardless of whether they are locked or unlocked.

Finally, it is an object of the present invention to provide fire-safety constructions and building constructions and latch assemblies which will be relatively simple and inexpensive to manufacture, easy to install, operate and repair, and rugged and durable in use.

Other objects and advantages of the present invention will become apparent from a consideration of the following description, taken in connection with the accompanying drawing, in which:

FIGURE 1 is a perspective view of a building construction embodying the present invention;

FIGURE 2.is an enlarged fragmentary cross-sectional view of a latch assembly according to the present invention; and

FIGURE 3 is a fragmentary side view of a portion of the structure shown in FIGURE 2.

Briefly stated, the present invention comprises the discovery that a latch member can be automatically released to permit opening of its associated closure in the event of a fire, if a latch keeper is provided that is maintained in operative position by a fusible link and that is mounted for movement out of operative position when the heat of a fire causes the fusible link to release the keeper.

Referring now to the drawing in greater detail, the invention is shown by way of example in the environment of a hatchway for use on the roof of a building. It will be understood, however, that the invention is adaptable wherever a closure of a building structure provides access to or from the interior of the building or between different portions of the interior of a building. Thus, the present invention is adaptable for use on windows and doors and other closures associated with building constructions, whether or not they are external or internal closures and whether or not they are horizontally or vertically arranged.

The illustrated embodiment includes a curb 1 that surrounds the opening of the hatchway and a cover 3 which closes the hatchway. A weather seal 5 seals between the upper edge of curb 1 and the cover 3 resting thereon in the closed position of the cover. The cover is hingedly mounted on curb 1 on a continuous hinge (not shown) for vertical swinging movement about a horizontal axis extending along one side of the cover 3 and one side of the upper edge of curb 1. A spring housing 9 is mounted on the inner side of curb 1 and comprises a pair of telescoping cylinders which contain a coil compression spring that continuously yieldably urges them apart. The lower cylinder is swingably mounted at its lower end for vertical swinging movement about a horizontal axis parallel to the cover hinge, while the upper cylinder of spring housing 9 is pivotally interconnected with a bracket 11 that is fixed on the underside of cover 3 a short distance from the axis of vertical swinging movement of cover 3. Cover 3 is thus continuously yieldably urged upwardly by a spring action at least strong enough to overcome the weight of cover 3.

A handle 13 is provided for raising and loweringcover 3 and is disposed on the upper or outer side of cover 3. Handle 13 is integral with a shaft 15 that rotatably extends through cover 3 and is rotatably mounted within a cylindrical sleeve 17 that is secured to cover 3. Collars 19 are secured to shaft 15 and are disposed on either side of sleeve 17 in bearing contact with sleeve 17. A handle 21 is integral with shaft 15 on the under or inner side of cover 3 for manipulation from within the build ing. The axis of rotation of shaft 15 is perpendicular to the axis of vertical swinging movement of cover 3.

Shaft 15 carries an integral latch member 23 that extends from shaft 15 in the opposite direction from handles 13 and 21. Latch member 23 is on the under or inner side of cover 3 and coacts with a keeper 25 to maintain cover 3 closed until handle 13 or 21 is turned. Keeper 25, in turn, is in the form of a metal plate that is carried by an upper inner portion of curb 1. Keeper 25 comprises a horizontally elongated plate that is disposed in a generally vertical plane. Keeper 25 terminates along its upper edge in a horizontal inwardly extending ledge 27. Keeper 25 is mounted on curb 1 by a hinge bolt 29 so that keeper 25 is vertically swingable about the horizontal axis provided by hinge bolt 29. The axis of hinge bolt 29, in turn, is perpendicular to the axis of vertical swinging movement of cover 3 and per pendicular to the axis of shaft 15 when cover 3 is closed. Hinge bolt 29 thus provides a pivotal mounting for keeper 25 adjacent one end of keeper 25. Adjacent its other end, keeper 25 is held in the operative position shown in FIGURES 2 and 3 by means of a fusible linkage 31 that is elongated in a direction generally parallel to the direction of upward movement of latch member 23 at the beginning of the door-opening movement. Linkage 31 includes a link 33 pivotally and detachably secured to keeper 25 by means of a bolt 35. Linkage 31 also includes a link 37 that is pivotally and detachably secured to curb 1 below keeper 25 by means of a bolt 39. Links 33 and 37 overlap each other over a substantial area and are secured together over that area by means of a fusible alloy 41 disposed between links 33 and 37 in the region of overlap. Fusible alloy 41 may be any of the usual lowmelting alloys used for fire-safety purposes, which are ordinarily alloys of bismuth, lead, tin and sometimes cadmium. For example, a suitable alloy designed to melt at 70 C. is 50% bismuth, 27% lead, 13% tin and 10% cadmium. A suitable alloy melting at C. is 56% bismuth, 40% tin and 4% zinc.

A guide bracket 43 provides a support and brace for keeper 25 in its lower or operative position, as seen in FIGURE 3. Guide bracket 43 thus reduces the dOWllward and lateral stresses that would otherwise be imposed on the relatively Weak fusible material of fusible linkage 31, so that the stresses to which fusible link 31 is subjected are almost solely tensile in an upward direction as a result of the upward force imposed on keeper 25 by latch member 23 under the influence of the spring in spring housing 9.

Means are provided for locking the latch assembly in the latched position shown in FIGURE 2, comprising for example an eye 45 that is secured to the under side of cover 3 closely adjacent handle 21 when latch member 23 is fully engaged under ledge 27 of keeper 25. A hasp lock 47 extends through eye 45 and encompasses handle 21 releasably to retain handle 21, and thus latch member 23, in the fully latched position of FIGURE 2 against unauthorized operation. A key 49 operates hasp lock 47. Of course, it will be understood that any other locking means for preventing unauthorized manipulation of handles 13 and 21 can be provided.

In use, cover 3 can be raised and lowered and latched closed by manipulation ofhandle 13 or 21 depending on whether cover 3 is being operated fromthe outside or the inside. When the assembly is closed and latched,-the

.latch member can be locked against unauthorized openring, and the cover 3 thus locked shut, by use of hasp lock 47 in the position shown in FIGURE 2.

Should fire break out within the building, however, and it becomes desirable to provide access to the interior of the building through the hatchway without unlocking lock 47, fusible linkage 31 will break soon after the. 7

temperature within the hatchway reaches the yield temperature of fusible alloy 41. When fusible linkage 31 thus breaks, latch member 23 pushes against the under side of ledge 27 of keeper 25, thereby swinging keeper 2.5 counterclockwise upwardly as shown by the direction of the full-line arrow of FIGURE 3. Latch member 23 rises upwardly and follows'an arc about the axis of the cover hinge, sliding along the under side of ledge 27,

the invention, as those skilled in this art will readily understand. Such modifications and variations are con- 7 sidered to be within the purview and scope of the present invention as defined by the appended claims.

What is claimed is:

1. In a building having an opening therein and a closure mounted on the building for swinging movement about a first axis between a closed position in which the closure closes theopening and an open position in which the opening provides access into 'or out of a portion of the building, latch means carried by the closure, and,

keeper means carried by the building for engagement by the latch means to maintain] the closure closed; the improvement comprising means mounting the keeper means for swinging movement relative to the building about a second axis perpendicular to said first axis and perpendicular to the direction of movement of the latch means as the latch means passes the keeper means, be-

' tween an operative position in which the keeper means coacts with the latch means to maintain the closure closed-and an inoperative position in whichfthe latch means passes the keeper means during closure opening movement, and fusible link means on said building connected to said keeper" means for maintaining the keeper means in saidoperative position in the absence of heat sufficient to weaken said fusible link means.

2. Apparatus as claimed in claim 1, in which the keeper means is mounted on an internal wall surface of the building and swings parallel to and .closely adjacent said surface, the keeper means comprising a web portion parallel to said surface and a flange projecting outwardly from the web away from said surface, the latchmeans engaging with the flange and the fusible link means engaging with the web.

References Cited in the file of this patent" UNITED STATES PATENTS 1 2983343 Lyons May 9, 1961 

1. IN A BUILDING HAVING AN OPENING THEREIN AND A CLOSURE MOUNTED ON THE BUILDING FOR SWINGING MOVEMENT ABOUT A FIRST AXIS BETWEEN A CLOSED POSITION IN WHICH THE CLOSURE CLOSES THE OPENING AND AN OPEN POSITION IN WHICH THE OPENING PROVIDES ACCESS INTO OR OUT OF A PORTION OF THE BUILDING, LATCH MEANS CARRIED BY THE CLOSURE, AND KEEPER MEANS CARRIED BY THE BUILDING FOR ENGAGEMENT BY THE LATCH MEANS TO MAINTAIN THE CLOSURE CLOSED; THE IMPROVEMENT COMPRISING MEANS MOUNTING THE KEEPER MEANS FOR SWINGING MOVEMENT RELATIVE TO THE BUILDING ABOUT A SECOND AXIS PERPENDICULAR TO SAID FIRST AXIS AND PERPENDICULAR TO THE DIRECTION OF MOVEMENT OF THE LATCH MEANS AS THE LATCH MEANS PASSES THE KEEPER MEANS, BETWEEN AN OPERATIVE POSITION IN WHICH THE KEEPER MEANS COACTS WITH THE LATCH MEANS TO MAINTAIN THE CLOSURE CLOSED AND AN INOPERATIVE POSITION IN WHICH THE LATCH MEANS PASSES THE KEEPER MEANS DURING CLOSURE OPENING MOVEMENT, AND FUSIBLE LINK MEANS ON SAID BUILDING CONNECTED TO SAID KEEPER MEANS FOR MAINTAINING THE KEEPER MEANS IN SAID OPERATIVE POSITION IN THE ABSENCE OF HEAT SUFFICIENT TO WEAKEN SAID FUSIBLE LINK MEANS. 